0436762 JOHNSON COVER, Carb. body

Illustration 1 g00651694
Test Step 1. Check for Connector Damage.
Turn the circuit breaker for the engine to the OFF position.
Turn the keyswitch to the OFF position.
Thoroughly inspect the ECM connectors J1/P1 and J2/P2. Inspect all of the other connectors. Refer to the diagnostic functional test Troubleshooting, "Inspecting Electrical Connectors" for details.
Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector that are associated with the circuit.
Check the ECM connector (allen head screw) for the proper torque of 6.0 N m (55 lb in).
Check the customer connector (allen head screw) for the proper torque of 2.25 0.25 N m (20 2 lb in).
Check the harness and the wiring for abrasion and for pinch points.Expected Result:The connectors and wiring should be free of following problems: damage, corrosion, abrasion and incorrect attachment.Results:
OK - The connectors and wiring are okay. Proceed to test step 2.
Not OK - The connectors and/or wiring are not okay.Repair: Repair the connectors or wiring and/or replace the connectors or wiring. Stop.Test Step 2. Check for an internal Short or Open in the Solenoid Coil.
Disconnect solenoid connector J126/P126.
Measure the resistance of the solenoid coil between J126-1 and J126-2.Expected Result:The resistance of the solenoid coil should be between 24 and 53 Ohms.Results:
OK - The resistance of the solenoid coil is between 24 and 53 Ohms. Proceed to test step 3.
Not OK - The resistance of the solenoid coil is not between 24 and 53 Ohms. The solenoid is internally shorted or open.Repair: Replace the solenoid. Stop.Test Step 3. Check the Voltage at the Solenoid.
Install the Caterpillar Electronic Technician (ET).
Turn the circuit breaker for the engine to the ON position.
Turn the keyswitch to the ON position. The engine should be OFF.
Select the override for the hydraulic engine retarder valve on the Cat ET.
Set the override to 100 percent.
Measure the voltage between P126-1 and P126-2 at the connector for the hydraulic engine retarder valve.
Disable the override.
Reconnect the solenoid connector J126/P126.Expected Result:The voltage should measure 24 3 VDC.Results:
OK - The voltage measures 24 3 VDC.Repair: The voltage reaches the solenoid. Check the mechanical operation of the solenoid. Stop.
Not OK - The voltage does not measure 24 3 VDC. Proceed to test step 4.Test Step 4. Check the Voltage at the ECM.
Turn the keyswitch to the OFF position.
Turn the circuit breaker for the engine to the OFF position.
Disconnect ECM connector J2/P2.
Remove wire E798-PK from ECM connector P2-29. Install a wire jumper into the socket for P2-29.
Remove wire E797-WH from ECM connector P2-35. Install a wire jumper into the socket for P2-35.
Turn the circuit breaker for the engine to the ON position.
Turn the keyswitch to the ON position. The engine should be OFF.
Select the override for the hydraulic engine retarder valve on the Cat ET.
Set the override to 100 percent.
Monitor the voltage between the wire jumpers in P2-29 and P2-35.
Disable the override.Expected Result:The voltage should measure 24 3 VDC.Results:
OK - The voltage measures 24 3 VDC. There is an open circuit or a short in the harness between the ECM and the solenoid.Repair: Repair the connectors or wiring and/or replace the connectors or wiring. Stop.
Not OK - The voltage does not measure 24 3 VDC.Repair: Replace the ECM. Refer to Troubleshooting, "Replacing the ECM". Stop.